The Realtec system on my ASUS mobo insists you tell it what's going on every time you plug something in. So you plug the mic into the port, and a window pops up requesting a specification of what you just plugged in. If you don't give it an answer, it will not turn the port on to use for anything. When you unplug, start back at the beginning - it does not remember what was plugged in last and use the old setting without confirmation.